We have recently begun experiencing random problems on the backfeed for dual tuners. TV2 will have a snowy screen regardless of modulator settings. This problem occurs in dual tuners of all types. Today it was a 322 model for me. Other guys have had the same problem on 625s. The only resolution each time is to remove the diplexers and run a direct line to TV2. We have tried different brand diplexers, coax, etc. It happens on both air and cable settings. It happens on both old and new TVs. We have tried different recievers in the same house with the same result, and yet can proceed to the next install and have no problems using the same equipment. Anyone out there had similar problems? Anyone out there with an answer?